Important scaling parameters for testing model-scale helicopter rotors

Singleton, Jeffrey D.; Yeager, William T.

doi:10.2514/6.1998-2881

Cited by 6 publications

(4 citation statements)

References 1 publication

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“…For this hovering case, the blade-tip Reynolds number was set to 5.27 · 10 [60]. Moreover, the low Reynolds number of the model-scale may cause premature separation which does not occur at full-scale as a result of the turbulent boundary layer.…”

Section: Analysis Of Elastic Blade Resultsmentioning

confidence: 99%

Accurate Predictions of Rotor Hover Performance at Low and High Disc Loadings

García

Barakos

2018

Journal of Aircraft

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This paper presents evidence on the ability of modern CFD methods to accurately predict hover performance of rotors with modest computer resources. The paper uses two well-studied blades, the S-76 main rotor blade and the XV-15 tiltrotor blade. The results are compared with experiments and show that the performance is well predicted. In addition, the employed Computational Fluid Dynamics method was able to capture the effects of the tip Mach number, tip shape, blade aeroelasticity, and flow transition on the performance of the blade as well as on the wake structure and the rotor acoustics.

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Section: Analysis Of Elastic Blade Resultsmentioning

confidence: 99%

Accurate Predictions of Rotor Hover Performance at Low and High Disc Loadings

García

Barakos

2018

Journal of Aircraft

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“…The importance of Reynolds number is well established in fixed wing aerodynamics. By contrast, in the case of rotary wing like the helicopters, it is still not well understood (57) . Moreover, the low Reynolds number of the model-scale may cause premature separation which does not occur at full-scale as a result of the turbulent boundary layer.…”

Section: Full-scale S-76 Rotor Bladementioning

confidence: 99%

CFD analysis of hover performance of rotors at full- and model-scale conditions

Barakos

García

2016

Aeronaut. j.

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Analysis of the performance of a 1/4.71 model-scale and full-scale Sikorsky S-76 main rotor in hover is presented using the multi-block CFD solver of Glasgow University. For the model-scale blade, three different tip shapes were compared for a range of collective pitch and tip Mach numbers. It was found that the anhedral tip provided the highest Figure of Merit. Rigid and elastic full-scale S-76 rotor blades were investigated using a loosely coupled CFD/CSD method. Results showed that aeroelastic effects were more significant for high thrust cases. Finally, an acoustic study was performed in the tippath-plane of both rotors, showing good agreement in the thickness and loading noise with the theory.For the anhedral tip of the model-scale blade, a reduction of 5% of the noise level was predicted.The overall good agreement with the theory and experimental data demonstrated the capability of the present CFD method to predict rotor flows accurately.Keywords : CFD, S76, Hover, Tip-shape.

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“…However when dealing with high speed forward flight aeroelastic stability, Mach scaled rotors are again required. Furthermore, performance testing of flexible rotors also implies the need for Mach Scaling 19,20 Next, it should be noted that the two pronged approach depicted in Fig. 2 applies to rotary-wing aeroelastic scaling just as well as it does to fixedwing problems.…”

Section: Additional Scaling Considerationsmentioning

confidence: 99%

Aeroelastic scaling for rotary-wing aircraft with applications

P.¹

2001

19th AIAA Applied Aerodynamics Conference

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This paper presents a new treatment of the aeroelastic scaling problem for rotary wing vehicles (i.e. helicopters and tiltrotors). It is shown that the offset hinged spring restrained blade model is the rotary wing equivalent of the typical cross-section that has been used during the last 50 years to obtain aeroelastic scaling laws for fixed wing vehicles. A new two-pronged approach for developing refined aeroelastic scaling laws for rotary-wing aeroelastic and aeroservoelastic applications is presented. It combines the classical approach with computer simulations to obtain new refined aeroelastic scaling relations. The rotary wing scaling laws are applied to the vibration reduction problem in helicopter rotors using an actively controlled, partial span, trailing edge flap. The results obtained for a Mach scaled rotor are compared with those obtained for a Proude scaled rotor. The results indicate that the Mach scaled rotor is needed so as to obtain the correct actuation requirements for vibration reduction.

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Important scaling parameters for testing model-scale helicopter rotors

Cited by 6 publications

References 1 publication

Accurate Predictions of Rotor Hover Performance at Low and High Disc Loadings

Accurate Predictions of Rotor Hover Performance at Low and High Disc Loadings

CFD analysis of hover performance of rotors at full- and model-scale conditions

Aeroelastic scaling for rotary-wing aircraft with applications

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